Horsepen Dam dam
Horsepen Dam
Horsepen Dam, located in Loudoun, Virginia, is a key asset for water supply purposes in the region. This earth-type dam stands at a height of 50 feet and spans a length of 600 feet, with a storage capacity of 15,200 acre-feet. The dam sits on Horsepen Run and is under the regulatory oversight of the Department of Conservation and Recreation in Virginia.
With a high hazard potential, Horsepen Dam is regularly inspected to ensure its structural integrity and overall condition. The most recent assessment in July 2021 deemed the dam to be in satisfactory condition. In the event of an emergency, the dam's emergency action plan (EAP) is essential for preparedness and response, although its last revision dates back to 2015. Horsepen Dam plays a crucial role in managing water resources in the area and highlights the importance of maintaining and monitoring infrastructure to mitigate potential risks associated with climate variability and water resource management.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Horsepen Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Broad Run Near Leesburg | 188 cfs | → |
| Goose Creek Near Leesburg | 67 cfs | → |
| Seneca Creek At Dawsonville | 72 cfs | → |
| Difficult Run Near Great Falls | 149 cfs | → |
| Limestone Branch Near Leesburg | 3 cfs | → |
| N F Goose Creek At Rt 729 Near Lincoln | 18 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Horsepen Dam.
Boat launches
- Ashburn Village Boulevard 20585, Lansdowne
- Edwards Ferry Road Montgomery County
- Rileys Lock Road Darnestown
- Smart's Mill Rd (Private) Leesburg
- Potomac Hills Street Fairfax County
- Clarksburg Road Germantown
Campgrounds
- Horsepen Branch
- Horsepen Branch Campsite
- Chisel Branch
- Chisel Branch Campsite
- Lake Fairfax
- Turtle Run Campsite
Fishing spots
- Washington Aqueduct
- Dalecarlia Reservoir
- Gillam Branch (Historical)
- Davis Branch (Historical)
- Maddox Branch
- Georgetown Reservoir
Paddle runs
- Bixler Bridge On State Route 675 To Karo Landing, Approximately 6 Miles South Of Town Of Front Royal
- Headwaters Adjacent To Fdt 573 To State Route 622 Bridge
- State Route 675 At Edinburg, Va To State Highway 55 Southeast Of Strasburg, Va
- Segment C--Nf Boundary To Confluence With North Fork Shenandoah River
- Segment B--State Route 730 Bridge To Nf Boundary
Track Horsepen Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Horsepen Dam
Where does the data for Horsepen Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the High hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Horsepen Dam.